Aloha to you all. I recently bought a 94 caterpillar 307 and had a minor issue with the arm attached to the bucket falling or moving in when joystick was released to neutral. Today while doing some cleaning the arm suddenly stopped comming down, but now no matter what position I put the joystick in or out the arm goes out only and doesnt want to come in. I also noticed to that a higher pitch hydraulic noise occurring. Anyone have ideas of what could be causing this condition? Thanks for your time. Scott
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Sounds almost like you have a lockout activating so your can't move the arms.... The noise sort of sounds like your relief. I was going to say maybe your axu hydraulics is stuck on but that usually gives a lack of lifting power but the arms will still be free to be lowered.
sounds like =the nut holding the piston to the shaft has been slowly loosening up and then it came all the way off ,to check that you could disconnect the two hoses to the cylinder and blow air thru either fitting to check for by pass , or unpin the chrome rod and try and pull it out the cylinder
Aloha again guys and thanks for the suggestions. I checked the cylinder today and it is okay; the piston holds under pressure of air and only moves a little then stops and no more air can go through.
I started the engine with the extend arm hose off and joystick in neutral. I immediately got high pressure oil shooting out of it. Just to be sure I took of the hoses of the bucket circuit and started machine and got no oil shooting out on start up. Only when I moved the joystick oil came out of the hoses.
I believe the problem is a stuck spool or valve and am about to open up that circuit but wanted to know if anyone has taken apart one with the devices or extensions of the valve body in the photos below. I don't want to open it up the wrong way and have check balls and springs fall out unexpectedly (which you should always expect). Any help would be appreciated.
You may be better posting this on the cat forum,I think most of the expertise here relates to bobcats not cat.
That is casing is the servo which shifts the spool , pretty simple to service , a piston inside that cap is pushed by low pilot pressure from the joy stick , the spring which centers the spool should be screwed into the end of the spool , so it won't jump out , your on the right track
Thanks fishfiles. Do you know if I need to remove both sides or can I slide out the spool on one side without any parts falling off inside? Also, do you take it off in two pieces(taking out the allen bolts and separating) or one piece?
From looking at the picture of your Cat I am not sure if both side caps would have to be taken off to slide the spool out , looks gray market to me , one has to come off for sure but what side is the spring on I can't tell you , I would call for a fax of the print of the control vlave to familiar myself with it before dissassembling it if you don't feel good about it , good luck with that as Cat prints are very hard to read ---I did a komtsu 200 recently that the spool stuck on the bucket curcuit , it was doing the same thing you are discribing , it was jammed up really bad , had to remove both caps as I had to use a brasss punch to knock it out , never thought it would be saveable , was able to polish the spool wth emery paper about 15 times till if finally slide in smooth , never did figure out what wet thru it to scare it up so bad
Found the problem and machine is operable again. Spool valve for the circuit was a little rusty in the middle area. Put some emery cloth to it and put everything back and it's as good as new. Thanks fishfiles, spool had spring on it as you described and oppositte side cap had to be removed. Mahalo for all your help; saved me time and money.
